Crane drive system



DeC- 7, 1965 J. G. GRALL ETAL CRANE DRIVE SYSTEM 4 Sheets-Sheet l Filed June 30. 1961 mmv H770 EY Dec. 7,'1965 J. G. GRALL ETAL 3,221,896

CRANE DRIVE SYSTEM Filed June 50, 1961 4 Sheets-Sheet 2 @amm A TTENE Y Filed June 30 1961 Dec. 7, 1965 J. G. GRALL ETAL CRANE DRIVE SYSTEM 4 Sheets-Sheet 5 /NVENTES Jahn 6? Grail Edvard Nickles @del Um Dejf@ Jbjzzz D. M95? Dec. 7, 1965 J. G. GRALL ETAL CRANE DRIVE SYSTEM 4 Sheets-Sheet 4 Filed June 30 1961 United States Patent O M' 3,221,896 CRANE DRIVE SYSTEM .lohn G. Grail and Edward B. Nickles, Manitowoc, Roche J. Van De Hey, Whitelaw, and John D. West, Manitowe c, Wis., assignors to Manitowoc Engineering Corporation, Manitowoc, Wis., a corporation of Wisconsin Filed June 30, 1961, Ser. l To. 121,179 18 Claims. (Cl. 212-38) This application is a continuation-in-part application of co-pending applications for United States Letters Patent, Serial Number 751,545, entitled, Drive System and Mechanism, filed July 28, 1958, now Method of Operating Same; filed July 18, 1962, now United States Patent NO. 3,120,896, issued February 11, 1964, wherein there is illustrated, described, disclosed and claimed a drive system for a machine such as an excavator crane which comprises a pair of separate engines, one for driving the swing function and the other for driving the hoist function of the machine, independently of each other, through appropriate fluid pressure responsive swing and hoist clutch devices which are each engageable and operable in response to a given fluid pressure range, and apparatus connected to a throttle for each of the engines and operable in response to fluid pressure ranges which are higher than the pressure range of the respective clutch device in a manner which enables the clutch devices to be engaged prior to the advancement of the respective engine throttle. By thus variably controlling the torque output of the swing and hoist engines, through the corresponding fluid pressure actuated throttles, relative to the engagement of the respective fluid pressure actuated clutch devices, the disadvantages and obejctions of the conventional type drive systems, as mentioned above, are overcome.

This invention relates to drive systems for operating machines, such as cranes having excavating attachments like shovels, clamshells or draglines attached thereto, and more particularly to an improved drive system for operating such machines, wherein controllable variable drive mechanisms are employed to power the hoist assembly and the swing asembly thereof.

lt is customary, in crane type excavators, to provide a single engine to drive the several functions of the machine, the power being transmitted and controlled by means of friction clutch devices. In such conventional systems the speed of the engine is customarily regulated which tends to hold a constant speed by varying the engine torque output to compensate for load changes. Accordingly, it is necessary for the clutch devices to slip while accelerating a load, resulting in the continual wear of the friction linings and requiring frequent adjustment and periodic replacement. This is particularly true of the swing clutch devices of the swing assembly of the machine which are usually employed to reverse the rotation of the crane by application of the appropriate clutch device to first decelerate the swing of the machine and then to accelerate the swing thereof in the opposite direction. During such a reversal of the swing of the machine it is necessary that the clutch device must slip until the crane reaches its governed swing speed, resulting in severe heating and wear of the friction surfaces of the swing clutch device.

A second drawback in the conventional type single engine crane drive systems lies in the inherent inability of a single engine to maintain a given speed under changing load due to governor droop. Thus, for example, an engine laboring under a hoisting load will be further slowed by the application of a swing load with the result that the cycle time is considerably greater than it would be if the swing speed of the machine were not reduced by the hoisting load thereof.

An additional drawback in the conventional drive systems for such machines results from driving both the hoist 3,Z2l,8% Patented Dec. 7, 1965 ICC and swing functions from the same power source whereby the speeds of these functions are not adjustable with respect to each other. As a result, it frequently happens that the speed of the hoist function is such that the load is raised to the maximum of the machine before the desired angle of swing is completed. It is then necessary to hold the load elevated with a brake until the swing is completed. Power is obviously wasted in such a cycle because the load is raised faster than necessary. The converse of this also occurs in some operations, i.e., the swing of the machine must be delayed until the hoist has lifted the load sufficiently to clear a high spoil pile. Such a delay results in cycle time wasted with a resulting loss of machine eiiiciency.

The drive system of this invention also contemplates the elimination of the disadvantages and objections of the customary or conventional types of drive systems, as mentioned above, and differs from the drive system of the above identified U.S. Patent Nos. 3,088,564 and 3,120,896 by employing a pair of controllable variable torque convertors, one for the swing function and the other for the hoist function, which may be driven by a single source of power, such as a common engine, or a plurality of sources, such as a pair of engines, and fluid pressure actuated apparatus which independently, separately and effectively varies the torque output from the variable torque convertors. The drive system of this invention also employs appropriate fluid pressure actuated swing and hoist clutch devices which are responsive to given uid pressure ranges with the apparatus for controllably varying the resulting output of the respective torque convertors being responsive to higher pressure ranges to enable the clutch devices to be engaged prior to an appreciable increase in the torque output of the respective torque convertor, while being able to maintain the output speed of the power source substantially constant.

Accordingly, it is an object of the present invention to provide a drive system for excavator cranes wherein the slipping of friction clutch devices and their consequent Wear is greatly reduced.

It is also an object of the invention to provide a drive system for excavator cranes wherein the swing speed of the crane is unaffected by the hoisting load thereof.

Another object of this invention is to provide a drive system for cranes wherein the swing and hoisting speeds thereof are individually variable.

Still another object of this invention is to provide apparatus for coordinating a control for `a friction clutch device with the load thereon.

An additional object of this invention is to provide a drive system for machinery such as excavating cranes wherein the swing and hoist functions are each operated by assemblies which include clutch devices which are driven by torque convertors and there is employed therewith fluid pressure actuating apparatus which enables the clutch device to be engaged prior to any appreciable increase of the torque output of the respective torque convertor so that slippage, wear and overheating of the clutch devices are substantially eliminated.

It is yet still another additional object of this invention to provide a drive system for machinery such as excavating cranes or the like wherein the hoist and swing functions thereof are operated by assemblies each of which includes a torque convertor and a clutch device with apparatus that enables the operating cycle time of the machinery in performing the hoist and swing functions to be decreased which results in a desired increase in the performance and production of the machinery.

Other objects and important features of this invention will be apparent from a study of the specification following taken with the drawing, which together show, describe,

disclose and illustrate the preferred embodiment together with a number of modifications of the invention and what are now considered to be the best modes of practicing the principles thereof. Still other embodiments or modifications may be suggested to those having the benefit of the teachings herein, and such other embodiments or modiiications are intended to be reserved as they fall within the scope and breadth of the sub-joined claims.

In the drawing:

FIGURE l is a top plan view of a part of a machine such as the upper works of an excavating crane having the drive system of thisinvention employed therein;

FIGURE 2 is an enlarged vertical sectional view through a torque convertor of the drive system illustrated in FIG. 1 taken along the line 2-2 therein looking inthe direction of the arrows;

FIGURE 3 is a vertical sectional view of the torque convertor illustrated in FIG. 2 taken along the line 3-3 therein looking in the direction of the arrows;

FIGURE 4 is a horizontal sectional view taken along the line 4-4 of FIG. 3 looking in the direction of the arrows;

FIGURE 5 is a fragmentary top plan view of a modication of the drive system of this invention;

FIGURE 6 is a fragmentary top plan view of another modification of the drive system of this invention;

FIGURE 7 is a top plan view of an additional modification of the drive system of this invention, and

FIGURE 8 is a schematic, partial side elevational view of the machine part as illustrated in FIGURE 1, taken along the line 8-8 looking in the direction of the arrows.

Attention is now directed to FIG. l of the drawing wherein there is illustrated a part 10 of a machine, such as the upper works of a crane assembly which is suitable for having various types of excavator mechanism, such as booms, Clipper sticks, shovels, draglines, clamshells, etc., or the like, attached thereto in a manner to effectively accomplish any number of desired functions.

The upper works 10 of the machine includes a bed or platform 12 which may be rotatably mounted on rollers in a manner as more fully described and disclosed in the above identified U.S. Patent Nos. 3,088,564 and 3,120,896, wherein the rollers ride on an upper surface of a roller path which is defined by a ring gear 11 to enable swinging of the upper works 10 about a generally vertically extending axis. A kingpin 13 is centrally xed in the ring gear 11 and serves to keep the upper works 10 centered. A swing pinion 15 engages internal gear teeth in the roller path to power the upper works 10 through the swinging movement as shown schematically in FIGURE 8 of the drawing.

The rotating bed 12 may be provided with a pair of trifurcated boom hinge members 14 at its forward end, stifeners in the form of side frames 16 extend along each side of the bed 12 for supporting the several shafts which comprise the operating machinery, and supports located adjacent to the rear of the bed 12 for supporting a source of power 18 for driving the machine hoist assembly and swing assembly, to be described in more detail hereinafter.

In the preferred embodiment of this invention, as illustrated in FIGURES 1 and 8 of the drawing, the source of power 18 includes a single engine 20, normally of the internal combustion type, which has the output shaft 22 thereof connected to a split drive gearing arrangement 24 having a pair of output shafts 26 and 28 drivingly connected to the input side of a pair of fluid pressure responsive, output controllable and variable, torque convertors 30 and 32, respectively.

The hoist assembly of the machine includes a pair of drum shafts 34-34 journaled in pillow blocks mounted on the side frames 16 of the bed 12 and driven through suitable gears 35 from a countershaft 36 which is similarly mounted on the side frames 16 and which, in turn, is driven through suitable gearing 37 from a pinion 38 which is integral with a sprocket 40. The sprocket 40 is driven by means of a chain 42 which in turn is driven from the output side of the torque convertor 32, which may be called the hoist torque convertor.

The swing assembly of the machine may include, as more fully described and disclosed in the above identified U.S. Patent Nos. 3,088,564 and 3,120,896, the aforementioned swing pinion which is mounted on a swing pinion shaft and is driven through suitable gearing from a vertical swing shaft 44. Mounted at the top of the swing shaft 44 is a swing bevel gear 46 which engages, and may be driven by, either one of a pair of bevel gears 48 which are rotatably mounted on a horizontal swing drive shaft 50 and driven by a pair of swing clutch devices 52 respectively, which are also mounted on the drive shaft 5t) and are driven thereby. The drive shaft 50 extends outwardly of the sprocket 40 and carries a sprocket 54 which is driven by means of a chain 56 from the output side of the torque convertor 3), which may be called the swing torque convertor. As shown in FIGURE 8 of the drawing, the other end of the swing shaft 44 is provided with a drive pini-on 51 for driving the swing pinion 15 through a gearing arrangement 53.

As shown in FIG. 1 of the drawing, the sprocket 40 and the pinion 38 are carried on anti-friction bearings 39, tapered roller bearings being shown, mounted on the horizontal swing drive shaft 50 whereby the sprocket 40 cannot drive the drive shaft 50 but is merely positioned thereby. This arrangement .is not a necessary part of the invention but is merely a convenient expedient for the conversion of a conventional machine to take advantage of the present invention. In this respect it is to be noted that in a conventional machine the pinion 38 is normally driven by the drive shaft 50 which, in turn, is driven by a single sprocket and thus, in a conventional machine, all of the machinery is driven from the drive shaft 50.

The source of power 18 may be provided with a conventional governor, including a throttle lever or other suitable means whereby the speed of the engine 20 may be varied but yet maintained at a constant operating speed.

Fluid pressure actuated drum clutch devices 58-58 are provided, each of which include a clutch spider 60 carried by each of the drum shafts 34 and rotatably driven thereby. Each of the clutch spiders 60 drives a clutch shoe 62 carried thereby in a conventional manner whereby the respective clutch shoe 62 may be caused to engage a clutch drum 64 carried by a cable drum 66 rotatably mounted on each of the drum shafts 34. It will thus be seen that when the clutch shoe 62 is caused to engage the clutch drum 64, the cable drum 66 will turn with the respective drum shaft 34.

For the sake of brevity, the operation of only one of the drum clutch devices 58 of the hoist assembly will be described and it is to be noted that the respective clutch shoe 62 is connected by suitable linkage to fluid pressure responsive control apparatus or actuating device such as a motor 68, shown schematically, carried by the clutch spider 60, which may comprise a cylinder 70 having a piston 72 therein. A bias 74 in the form of a spring is provided to retract the clutch shoe 62 when Huid pressure is not being applied to the piston 72 to engage the clutch device 58.

Fluid pressure to operate the clutch device 58 is supplied through an axial passage 76 in the respective drum shaft 34, a rotary joint 78 and a line 80, from a modulating control valve 82 or 102 as the case may be at the operators station, which in turn is supplied from a pressure fluid source 87 through conduit means 89, note FIGURE 1 of the drawing.

As illustrated in FIGS. 2-4 of the drawing, the controllable variable torque convertors 30-32 are each provided with fluid pressure responsive control structure or apparatus 84 for variably controlling the output torque thereof and in each instance, the apparatus 84 includes a member 86, in the form of a sleeve, which is axially movable or slidable, relative to the respective torque convertor, over the outside diameter of an impeller 88. and by moving or sliding the sleeve member 86 it is possible to regulate the flow of fluid between the impeller 88 and the turbine 96 of the respective torque convertor and thereby controllably vary the torque youtput thereof while the input speed yfrom the source of power 18 may be maintained substantially constant.

The control structure or apparatus 84 also includes an actuating device 92, more clearly shown in FIGS. 2, 3 and 4 of the drawing, in the form of a pivotally mounted yoke member 94 which engages pins 9S disposed on each of the sleeve members 86 to axially slidably or movably position the respective sleeve member 86 relative to the impeller 88 and the turbine 9G of the respective torque convertor 30 yor 32.

Fluid pressure responsive control apparatus or actuating device such as a motor 96 is provided to operate the yoke member 94 of the apparatus 84 of the hoist torque convertor 32 in a manner which enables the torque output of the hoist torque convertor 32 to be increased as a result of the movement of the sleeve member 86 upon application of uid pressure and a bias 98 in the form of a spring is provided to decrease t-he torque output of the hoist torque convertor 32 when fluid pressure is reduced. The motor 96 is supplied with uid pressure from the operators control valve 82 through a line G.

While only the front cable drum 65 is shown and described in detail, it should be understood that the rear cable drum 66 is similar in construction and operation and is controlled by a similar but separate modulating control valve 102.

Because both cable drums 66, 66 are driven from the same hoist torque convertor 32, it is necessary that the pressure motor 9e be operable from either of the modulating valves 82, 162. It is, therefore, necessary to provide means to prevent feedback from the control line 1191i, when it is charged from one modulating valve, from entering the other clutch pressure line and thus engaging both of the drum clutch devices 58, 58.

A shuttle valve 104 serves as a convenient expedient for such feedback prevention. The shuttle valve 1154 comprises a cylinder 1116 having an inlet passage terminating in a valve seat 108 at each end and an outlet passage 110 at its center. A shuttle 112 comprising a valve spool is freely movable in the cylinder 1% and can seal against either valve seat 10S. It should be apparent that when the control valve 102 is opened to engage the rear drum clutch device 58, pressure fluid will enter the shuttle valve 104 and hold the shuttle 112 against the opposite inlet port thus preventing the passage of fluid to the front drum clutch device 58, but permitting fluid to flow to the rear drum clutch device 58. When modulating control valve 102 is closed and the control valve 82 is opened to engage the front drum clutch device 58, pressure Huid will force the shuttle 112 to the opposite end of the cylinder 1116 where it seals against the inlet seat and prevents pressure fluid from entering the rear drum clutch line. The shuttle 112 will, of course, move beyond the outlet and thus permit fluid to enter the line 161) to actuate the hoist torque convertor fluid pressure motor 96. Thus either modulating control valve 82, 1132 may be used to actuate the respective drum clutch device 58 and the output of the hoist torque convertor 32 without affecting the other drum clutch device. In the event that both modulating control valves 82, 1&2 are opened at the same time, the one which is opened to the greater pressure setting will determine the position of the shuttle 112 and thus the torque output of the hoist torque convertor 32.

An essential feature of the present invention relates to enabling the uid pressure responsive control apparatus or actuating devices 68 to be responsive to a lower range of control pressures than the hoist torque convertor fluid pressure responsive control apparatus or actuating device 96. This may be accomplished through the proper selection of springs and cylinder sizes and/ or through the use of suitable linkage (not shown). Because the clutch devices 58-58 respond to pressures which are less than those required to actuate the control apparatus 84 for the hoist torque convertor 32, the clutch device 53 will be engaged by increasing control pressure before the output torque of the torque convertor 32 starts to increase by an appreciable amount. Since at this point the source of power 18 is at a constant speed, and the torque output from the hoist torque converter 32 is very low, engagement or application of the drum clutch devices 58-58 is accomplished with a minimum of clutch wear due to the absence of high speed, high torque slippage.

As fluid pressure in the control system is further increased by the operator by means of the modulating valve 82 or 102, the torque convertor fluid pressure motor 96 will actuate the yoke member 94 and position the sleeve member 86 to cause the output torque of the hoist torque convertor 32 to increase and consequently the torque ultimately available at the drum, to increase. However, that same pressure is available at the drum clutch device 58 to increase the pressure of the clutch shoe 62 on the drum 64 to permit it `to transmit more torque. Thus the drum clutch devices 58 are always capable of transmitting the torque which is transmitted to them. While clutch slippage is kept to a minimum by the present drive system, it should be noted that at light loads theclutch devices 58, 5S may be engaged very gently with consequent slippage when it is desired to accelerate a load extremely slowly. However, since this slippage occurs only at light loads and slow relative speeds, the clutch life is not appreciably affected.

Construction and operation of the swing clutch devices 52, 52 of the swing assembly are similar to that of the hoist clutch devices. A pair of modulating valves 114, 116 is connected to the pressure uid source 87 by the conduit means 89 and through suitable piping and duplex rotary seal 118, to a pair of passages and 117 in the swing drive shaft 50 and thence to fluid motors incorporated in swing clutch devices 52, 52. A shuttle valve is connected between the two clutch control lines and has its outlet connected to another torque convertor fluid pressure responsive control apparatus or actuating device such as motor 122 for the swing torque convertor 30.

The fluid pressure for actuating the swing clutch devices 52, 52 and the uid motor 122 for the swing torque convertor 31) in the swing assembly are balanced in the same manner as those of the hoist assembly so that the swing clutch devices 52, 52 will be engaged or applied before the output torque of the swing torque convertor 3G is increased by an appreciable amount so that the swing clutch devices 52, 52 will be engaged with a minimum of slip.

The hoist clutch valves 82 and 102 as well as the swing clutch valves 114 and 116 may be conveniently arranged in associated pairs to be controlled by a single actuator (not shown) which will operate either valve depending upon the direction of motion from a neutral position, thereby permitting control in either direction with a single lever for each pair of valves.

In actual practice it has been found that a Midland valve, No. XN 3440, manufactured by Midland-Ross Corporation of Owosso, Michigan, works satisfactorily as the control valves 82, 102, 114 and 116 and while these valves have been illustrated in schematic manner in the drawing, it is to be understood that such valves may be of the type such as that identified above or some other like type of valve.

All of the control valves may be supplied, if desired, from the common source S7 of fluid under pressure which may be in the form of pressure fluid from an engine driven source (not shown) which may supply a distribution manifold to which each valve is connected.

An embodiment or modification of the drive system of this invention is illustrated in FIG. of the drawing, wherein the source of power or power source 18 includes a pair of engines 220-222 having the output shafts 226, 228 thereof connected directly to the input side of fiuid pressure reponsive torque convertors 230, 232 with the torque convertor 230 and the engine 220 associated therewith being a part of the swing assembly, while the torque convertor 232 and the engine 222 associated therewith are a part of the hoist assembly of the machine. In this embodiment or modification of the invention, the split drive gearing arrangement 24 of the embodiment as illustrated in FIG. 1 of the drawing, is eliminated and the swing torque convertor 230 and the hoist torque convertor 232 are independently and separately driven by the respective engines 220, 222. The torque output of the swing torque convertor 230 and the hoist torque convertor 232 are independently and effectively controlled and varied, in the same manner as the torque convertors 30 and 32 of the embodiment as illustrated in FIG. l of the drawing, by reason of the fiuid pressure responsive control apparatus or actuating devices 84, 96 and 122 so that in the modification or embodiment of the invention as shown in FIG. 5 of the drawing, the hoist clutch devices 58, 58 of the hoist assembly may be engaged prior to an appreciable increase in the torque output of the hoist torque convertor 232 while the output speed of the associated hoist engine 222 is maintained substantially constant and the swing clutch devices 52, 52 of the swing assembly may be actuated prior to an appreciable increase in the torque output of the swing torque convertor 230 while the output speed of the associated swing engine 220 is maintained substantially constant.

Also, it is to be understood that the output speeds of the hoist and swing engines 220- 222 may be maintained at substantially the same amount, if desired, or it may be advantageous that the respective output speeds of the hoist and swing engines be maintained substantially constant but at different amounts.

Another embodiment or modification of this invention is illustrated in FIG. 6 of the drawing, wherein there is shown a source of power 18 which includes a single engine 320 having the output shaft 322 thereof acting through a split drive gearing 324 with the output shafts 326 and 32S of the split drive gearing 324 each driving a friction clutch device 300, 302, preferably of the multiple disc type, as illustrated, which in turn are operable to drive the swing troque convertor 330 and the hoist torque convertor 332, respectively. In this embodiment of the invention, the friction clutch device 300 may be considered as part of the swing assembly while the friction clutch device 302 may be considered as part of the hoist assembly and the fluid pressure responsive motors 122 and 96 are connected by the yoke members 94 to the clutch devices 300, 302 rather than to the swing and hoist torque convertors 330 and 332, as in the previous modifications or embodiments of the invention as shown in FIGS. 1 and 5 of the drawings. Similarly, the clutch devices 300, 302 are actuated and engaged by reason of the fluid pressure responsive control apparatus or actuating motors 122 and 96 in a manner so that the swing clutch devices 52, 52 and the hoist clutch devices 58, 58 are engaged prior to any appreciable increase in the output of the clutch devices 300, 302, respectively, so that the output torque from the swing and hoist torque convertors 330 and 332 is variably controlled in a manner so that the swing clutch devices 52, 52 will be engaged prior to any appreciable increase in the output torque of the swing torque convertor 330 while the hoist clutch devices 58, 53 will be engaged prior to any appreciable increase in the output torque of the hoist torque convertor 332.

An additional embodiment or modification of this invention is shown and illustrated in FIG. 7 of the drawing, wherein the power source 18 includes a pair of engines 420, 422 similar to the embodiment or modification of the invention as shown in FIG. 5 of the drawing. The respective output shafts of the engines 420, 422 are operably connected to friction clutch devices 400, 402, preferably of the multiple disc type as illustrated, which are similar in construction to the clutch devices 300, 302, as illustrated in the modication of the invention as shown in FIG. 6 of the drawing. The clutch devices 400, 402 are each in turn operably connected to the input side of torque convertors 430 and 432 so that the engine 420, and the clutch device 400 which are associated with the torque convertor 430 may be considered as being a part of the swing assembly while the engine 422 and the clutch device 402 which are associated with the hoist torque convertor 432 may be considered as a part of the hoist assembly of the machine. As in the embodiment or modification of the invention as illustrated in FIG. 6 of the drawing, the fluid pressure responsive control apparatus or actuating devices 122 and 96 are connected to the clutch devices 400, 402, respectively, in a manner so that the output thereof may be controlled in a manner to vary the torque output of the swing 430 and the hoist 432 torque convertors so that the swing clutch devices 52-52 and the hoist clutch devices 053-58 may each be engaged prior to any appreciable increase in the torque outputs of the swing 430 and the hoist 432 torque convertors respectively.

In the operation of the modifications or embodiments of this invention as illustrated in FIGS. 6 and 7 of the drawing, the fiuid pressure responsive control apparatus or actuating devices 122 and 96 effectively slip the clutch devices 300, 400 and 302, 402, respectively in a manner which decreases the torque input into the torque convertors 330, 430 and 332, 432, respectively. Since the torque output of the torque convertors varies as the speed of the input thereinto, a small amount of slippage in the clutch devices 300, 400 and 302, 402 will result in a large change in the torque output of the torque convertors 330, 430 and 332, 432 respectively.

It is to be noted that in each of the modifications or embodiments of this invention as illustrated in FIGS. 1, 5, 6 and 7 of the drawing, that it is the torque output of the torque convertors which is controllably variable in a manner which enables the associated clutch devices to be engaged prior to any appreciable increase in the torque output of the associated torque convertor and that the source of power may be maintained with the output speed thereof being substantially constant.

In the invention as illustrated, described, disclosed and claimed in the U.S. Patent Nos. 3,088,564 and 3,120,896, identified above, the output of the source of power was controllably varied in a manner which enabled the respective clutch devices to be engaged prior to the increase in the torque output of the source of power.

On the other hand, this invention relates to a drive system for machines, such as excavator cranes, wherein there is employed a controllable variable torque convertor which is driven by a power source that has a substantially constant output speed with the torque convertor being responsive to fluid pressure so that the torque output of the torque convertor may be varied in a manner which enables the associated clutch devices to be engaged prior to any appreciable increase in the torque output of the torque convertor, while maintaining the output speed of the power source substantially constant. In U.S. Patent Nos. 3,088,564 and 3,120,896, it was the torque output of the source of power which was varied in a manner so that the associated clutch device could first be engaged and then the torque output of the power source could be increased.

From the foregoing, it is believed that there has been described, disclosed, illustrated and shown an improved drive system for operating a machine, such as a crane assembly having an excavator mechanism attached thereto, in which the slippage and consequent wear and overheating of the clutch devices associated therewith is minimized; in which the speed of the swing function is entirely independent and separate from the speed of the hoist function; in which the swing and hoist functions are individually and separately controlled without necessitating the inclusion of additional controls; in which the capacities of the friction clutch devices are co-ordinated with the requirements of the loads, and in which the cycle time for the swing and hoist functions may be substantially decreased so as to increase the operational production of the machine.

While the invention has been described, disclosed, illustrated and shown in terms of the preferred embodiment and a number of arrangements or modifications thereof, the scope of this invention should not be deemed to be limited by the embodiments, modifications and arrangements as herein shown, such other embodiments, modications and arrangements being intended to be reserved especially as they fall within the scope of the claims here appended.

We claim as our invention:

1. In combination with a crane having a source of power, a hoist assembly and a swing assembly driven by said source of power, a drive system for said assemblies comprising a torque convertor driven by the source of power and a clutch device driven by the torque convertor, fluid pressure responsive apparatus for controllably varying the torque outputs of the torque convertors relative to the engagement of the corresponding clutch device to enable the clutch devices to be engaged prior to an appreciable increase in the torque output of the corresponding torque convertor while the output speed of the source of power may be maintained substantially constant, said apparatus comprising control structure for controllably varying the torque outputs for each of the torque convertors by regulating Huid flow therethrough, a Huid pressure responsive actuating device connected to each of the control structures of the torque converters and to each of the clutch devices for enabling the clutch devices to be engaged, said fluid pressure responsive clutch engaging actuating devices being responsive to a lower range of fluid pressure than the corresponding uid pressure responsive torque convertor output regulating control structure actuating device of the respective assembly, and means for enabling the torque outputs of the torque convertors to be continuously varied after the respective clutch device has been engaged.

2. The crane as set forth in claim 1 wherein said source of power comprises a single engine driving each of said torque convertors through a split drive arrangement.

3. The crane as set forth in claim 1 wherein said source of power comprises a plurality of engines, one for each torque convertor, with the corresponding engine being in driving connection with the respective torque convertor.

4. The crane as set forth in claim 1 wherein said source of power comprises a single engine driving each of the torque convertors through a drive arrangement, and said apparatus comprises a clutch device interposed between the drive arrangement and each of the torque convertors.

5. The crane as set forth in claim 1 wherein the source of power comprises an engine for each of the torque convertors, and said apparatus comprises a clutch device interposed between the engine and the torque convertor of each of the assemblies.

6. The crane as set forth in claim 1 wherein each of the uid pressure responsive actuating devices comprise a piston-cylinder arrangement having a bias with the pistoncylinder arrangements of the clutch engaging devices being responsive to the lower range of fluid pressures than the piston-cylinder arrangements of the corresponding torque convertor actuating device of the respective assembly,

and a source of pressure uid connected to the actuating devices.

7. The crane as set forth in claim 6 wherein the cylinders of the piston-cylinder arrangements which are associated with the clutch engaging devices are of smaller cross-sectional area than the cylinder of the piston-cylinder of the piston-cylinder arrangement for the torque converter device that is associated therewith.

8. The crane as set forth in claim 6 wherein the bias of the piston-cylinder arrangements that are associated with the clutch engaging devices are weaker than the bias of the piston-cylinder arrangement for the torque converter device that is associated therewith.

9. A drive system for a crane comprising, in combination, a power source, a torque convertor driven by said power source, a clutch device driven by said torque convertor, fluid pressure actuated apparatus for enabling said clutch device to lbe engaged prior to any appreciable increase in the torque output of the torque convertor, sa-id apparatus comprising control structure for controllably varying the torque outputs for each of the torque converters by regulating fluid flow therethrough, a fluid pressure responsive actuating device connected to each of the control structures of the torque converters and to each of the clutch devices for enabling the clutch devices to be engaged, said fluid pressure responsive clutch engaging actuating devices being responsive to a lower range of fiuid pressure than the corresponding fiuid pressure responsive torque converter output regulating control structure actuating device of the respective assembly, and valving means for enabling the torque outputs of the torque converters to be continuously varied after the respective clutch device has been engaged.

10. A drive system for a crane having a hoist assembly driven by a controllably variable output type torque converter through a clutch device, said drive system comprising, fluid pressure actuated apparatus for enabling said clutch device to be engaged prior to any appreciable increase in the torque output of the torque convertor, said apparatus comprising control structure for controllably varying the torque outputs for each of the torque converters by regulating `fluid flow therethrough, a fluid pressure responsive actuating device connected to each of the control structures of `the torque converters and to each `of the clutch devices for enabling the clutch devices to be engaged, said fluid pressure responsive clutch engaging actuating devices being responsive to a lower range of fluid pressure than the corresponding fluid pressure responsive torque converter output regulating control structure actuating device of the respective assembly, and a common source of modulated pressure liuid connected t-o the actuating devices.

11. A drive system for a crane having a swing assembly driven by a controllably variable output type torque converter through a clutch device, said drive system comprising, fluid pressure actuated apparatus for enabling said clutch device to be engaged prior to any appreciable increase in the torque output of the torque convertor, said apparatus comprising control structure for controllably varying the torque outputs for each 'of the torque converters by regulating iiuid flow therethrough, a uid pressure responsive actuating device connected to each of the control structures of the torque converters and to each of the clutch devices for enabling the clutch devices to be engaged, said fluid pressure responsive clutch engaging actuating devices being responsive to a lower range of fluid pressure than the corresponding fluid pressure responsive torque converter output regulating control structure actuating device of the respective assembly, and a common source of modulated pressure fluid connected to the actuating devices.

12. In an excavator crane having a power source for driving a swing assembly and a hoist assembly, each of said assemblies comprising a torque convertor driven by said power source and a clutch device driven by the respective torque convertor, the improvement comprising, in combination with said swing and hoist assemblies of uid pressure responsive mechanism for enabling the clutch devices to be engaged prior to any appreciable in crease in the torque output of the corresponding torque convertor while the output speed of the power source may be maintained substantially constant, said mechanism comprising a fluid pressure responsive actuating device connected to the torque converter for controllably varying the output thereof by regulating the iluid ow therethrough and to the clutch device for enabling the clutch device to be engaged, said fluid pressure responsive clutch engaging actuating device being responsive to a lower range of uid pressure than the corresponding fluid pressure responsive torque converter output regulating actuating device, and means for enabling the torque output of the torque converter to be continuously varied after the respective clutch device has been engaged.

13. A drive system for a machine comprising, in combination, a source of power, a torque convertor driven by the source of power, a clutch device driven by the torque convertor, fluid pressure responsive apparatus for enabling the clutch device to be engaged prior to any appreciable increase in the torque output of the torque convertor, and means for continuously varying the torque output of the torque converter after the clutch device has been engaged.

14. A drive system for a machine comprising, in comb-ination, a source of power, a torque convertor driven by the source of power, a clutch device driven by the torque convertor, apparatus vfor controllably varying the torque output of the torque convertor relative to the engagement of the clutch device to enable the clutch device to be engaged prior to any appreciable increase in the torque output of the torque convertor while the output speed of the source f -power may be maintained substantially constant, said apparatus comprising a fluid pressure responsive actuating device connected to the torque convertor for controllably varying the torque output thereof, a fluid pressure responsive actuating device connected to the clutch device for enabling the clutch device to be engaged, said uid pressure responsive clutch engaging device being responsive to a lower range of fluid pressure than the fluid pressure responsive torque convertor actuation device, each of said uid pressure responsive actuating devices comprising a piston-cylinder arrangement having a bias with the .piston-cylinder arrangement of the clutch engaging device 'being responsive to the lower range of uid pressures than the piston-cylinder arrangement of the torque converter actuating device, and a common source of modulated pressure liu-id connected to the actuating devices.

1S. In a drive system for a machine having a power source, a torque convertor driven by said power source and a clutch device driven by said torque convertor, the improvement comprising, in combination with the torque convertor and the clutch device, fluid pressure actuated apparatus for enabling said clutch device to be engaged prior to any appreciable increase in the torque output of the torque convertor, said apparatus comprising control structure for controllably varying the torque output for the torque converter by regulating fluid flow therethrough, a uid pressure responsive actuating device connected to the control structure of the torque converter and to the clutch device for enabling the clutch device to be engaged, said uid pressure responsive clutch engaging actuating device being responsive to a lower range of fluid pressure `than the corresponding uid pressure responsive torque converter output regulating control structure actuating device, and valving means for enabling the torque output of the torque converter to be continuously varied after 'the respective clutch device has been engaged.

16. Apparatus for variably controlling the torque output of a torque convertor relative to the engagement of a clutch device driven by said torque convertor, said apparatus comprising a iluid pressure responsive actuating device connected to the torque convertor for controllably varying the torque output thereof, a fluid pressure responsive actuating device connected to the clutch device for enabling the clutch device to be engaged, said fluid pressure responsive clutch engaging device being responsive to a lower range of fluid pressure than the Huid pressure responsive torque convertor actuation device, each of said tluid pressure responsive actuating devices comprising a piston-cylinder arrangement having a bias with the pistoncylinder arrangement of the clutch engaging device being responsive to the lower range of uid pressures than the piston-cylinder arrangement of the torque converter actuating device, and a source of pressure uid connected to the actuating devices.

17. In a machine having a 4power source for driving a controllably variable output type torque convertor and a clutch device driven by the torque convertor, the improvement comprising, in combination with the torque convertor and the clutch device of fluid pressure responsive mechanism for enabling the clutch device to be engaged prior to any appreciable increase in the torque output of the torque convertor while the output speed of the power source may be maintained substantially constant said mechanism comprising a uid pressure responsive actuating device connected to the torque convertor and to the clutch device for enabling the clutch device to be engaged, said fluid pressure responsive clutch engaging actuating device being responsive to a lower range of fluid pressure than the fluid pressure responsive torque converterV actuating device said fluid pressure responsive actuating device comprising a piston-cylinder arrangement having a bias.

1S. In combination with a crane having a source of power, a hoist assembly and a swing assembly driven by said source of power, a drive system for the assemblies, said drive system comprising a controllably variable output type torque convertor driven by the source of power and a clutch device driven by the torque convertor, and apparatus for enabling the clutch devices to be engaged prior to an appreciable increase in the torque outputs of the corresponding torque convertor, said apparatus comprising a fluid pressure responsive actuating device connected to each of the torque convertors for controllably varying the respective torque output thereof, a fluid pressure responsive actuating device connected to each of the clutch devices for engaging the respective clutch device, said fluid pressure responsive clutch engaging devices being responsive to a lower range of tluid pressure than the corresponding fluid pressure responsive torque convertor actuation device of each of the assemblies, a source of modulated pressure fluid connected to the actuating devices and means for enabling the torque output of the torque converter for each assembly to be controllably varied after the engagement of the respective clutch device.

References Cited by the Examiner UNITED STATES PATENTS 2,203,177 6/1940 Patterson 192-3.2 2,363,860 1l/1944 Gentry 254-185 2,370,661 3/1945 Hayes 254-186 2,738,650 3/1956 McAfee.

2,753,738 7/1956 OLeary 192-3.2 2,787,172 4/ 1957 Gros.

2,992,713 7/1961 Stump et al 192-3.2

FOREIGN PATENTS l390,858 4/1933 Great Britain.

SAMUEL F. COLEMAN, Primary Examiner.

THOMAS I HICKEY, ANDRES H. NIELSEN,

Examiners. 

1. IN COMBINATION WITH A CRANE HAVING A SOURCE OF POWER, A HOIST ASSEMBLY AND A SWING ASSEMBLY DRIVEN BY SAID SOURCE OF POWER, A DRIVE SYSTEM FOR SAID ASSEMBLIES COMPRISING A TORQUE CONVERTER DRIVEN BY THE SOURCE OF POWER AND A CLUTCH DEIVCE DRIVEN BY THE TORQUE CONVERTOR, FLUID PRESSURE RESPONSIVE APPARATUS FOR CONTROLLABLY VARYING THE TORQUE OUTPUTS OF THE TORQUE CONVERTERS RELATIVE TO THE ENGAGEMENT OF THE CORRESPONDING CLUTCH DEVICE TO ENABLE THE CLUTCH DEVICES TO BE ENGAGED PRIOR TO AN APPRECIABLE INCREASE IN THE TORQUE OUTPUT OF THE CORRESPONDING TORQUE CONVERTER WHILE THE OUTPUT SPEED OF THE SOURCE OF POWER MAY BE MAINTAINED SUBSTANTIALLY CONSTANT, SAID APPARATUS COMPRISING CONTROL STRUCTURE FOR CONTROLLABLY VARYING THE TORQUE OUTPUTS FOR EACH OF THE TORQUE CONVERTORS BY REGULATING FLUID FLOW THERETHROUGH, A FLUID PRESSURE RESPONSIVE ACTUATING DEVICE CONNECTED TO EACH OF THE A CONTROL STRUCTURES OF THE TORQUE CONVERTERS AND TO EACH OF THE CLUTCH DEVICES FOR ENABLING THE CLUTCH DEVICES TO BE ENGAGED, SAID FLUID PRESSURE RESPONSIVE CLUTCH ENGAGING ACTUATING DEVICES BEING RESPONSIVE TO A LOWER RANGE OF FLUID PRESSURE THAN THE CORRESPONDING FLUID PRESSURE RESPONSIVE TORQUE CONVERTER OUTPUT REGULATING CONTROL STRUCTURE ACTUATING DEVICE OF THE RESPECTIVE ASSEMBLY, AND MEANS FOR ENABLING THE TORQUE OUTPUTS OF THE TORQUE CONVERTERS TO BE CONTINUOUSLY VARIED AFTER THE RESPECTIVE CLUTCH DEVICE HAS BEEN ENGAGED. 